Small changes in environmental temperature can significantly alter comfort levels. For hospital patients, as well as for campers, military personnel or even the homeless caught or subjected to cold environments, maintaining a comfortable environmental temperature may be critical to health or ability to sleep. Even a 2 to 3 degree change in temperature can alter the sense of comfort by a subject. Currently, items such as heated blankets, hot air blowers or hot water mattresses are required to raise the surrounding temperature in these environments.
Unfortunately, it is often the case that a subject does not have such equipment available to them, or it is not practical for a subject to carry such equipment. Therefore, there is a need in the art for a heat retention device and system that efficiently utilizes the warmer temperature of exhaled breath to help maintain body heat and/or reduce heat loss. The present invention satisfies this need.